Traditional soil monitoring methods have problems such as limited sampling points, low monitoring frequency, and slow data update. In order to solve the related problems, a soil monitoring system is designed in this paper based on LoRa. This system consists of several sensor nodes and a gateway. Each sensor node uses STM32 as the main control, and collects data such as soil temperature and humidity, pH, and NPK content through five-pin soil multi-parameter sensors. Each node forms a sensor network by means of LoRa. The gateway node uploads the data to Aliyun IoT platform through WiFi after collecting the data. We also designed a wechat applet to realize real-time monitoring of mobile terminals and timely warning of soil environment changes. The experimental results show that the system designed in this paper shows high performance under different soil types and parameters, which ensures the reliability and effectiveness of this system and provides a reliable solution for soil monitoring.